ר׳ יצחק בן יעקב אלפסי

ר׳ יצחק בן יעקב אלפסי (1013–1103), universally known by the acronym הרי״ף, was a Maghrebi Talmudist and one of the decisive architects of medieval halakhah. He was born at Qalʿat Bani Hammad in present-day Algeria and studied in Kairouan; ר׳ אברהם אבן דאוד names ר׳ חננאל בן חושיאל and ר׳ נסים בן יעקב as his teachers, although the Rif does not identify them as such in his surviving writings. He later became associated with Fez, where the standard scholarly reconstruction places his long mature career, academy and much of his literary work. In 1088, at about seventy-five, enemies denounced him to the authorities on an unknown charge, forcing him to flee to al-Andalus. After several months in Córdoba, he settled in Lucena and in 1089 succeeded ר׳ יצחק אבן גיאת as head of its yeshivah. His ספר ההלכות, also called הלכות רב אלפס, extracts and adjudicates the practically operative law of twenty-four Babylonian Talmud tractates while preserving enough argument to show the basis of its rulings. It became the most important halakhic code before משנה תורה and later one of the three principal authorities used by ר׳ יוסף קארו. Hundreds of responsa, many originally in Judeo-Arabic, also survive. His leading students included ר׳ יוסף אבן מיגאש, ר׳ יהודה הלוי, ר׳ אפרים מקלעת חמאד and ר׳ ברוך אבן אלבאליה. Before his death in Lucena, he chose ר׳ יוסף אבן מיגאש—not his scholarly son ר׳ יעקב—as his successor.